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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #386869
Research Project: Improving Lifetime Productivity in Swine

Location: Livestock Bio-Systems

Title: Testicular transcriptomics in GnRHR-II knockdown boars

Author
item DESAULNIERS, AMY - University Of Nebraska
item WIJESENA, HIRUNI - US Department Of Agriculture (USDA)
item CEDERBERG, REBECCA - University Of Nebraska
item Lindholm-Perry, Amanda
item Keel, Brittney
item ROSS, CAITLIN - University Of Nebraska
item ELSKEN, DOROTHY - University Of Nebraska
item Lents, Clay
item WHITE, BRETT - University Of Nebraska

Submitted to: Biology of Reproduction
Publication Type: Abstract Only
Publication Acceptance Date: 9/24/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Swine are the only livestock which produce both the second mammalian form of GnRH (GnRH-II) and its cognate receptor (GnRHR-II). Mounting evidence suggests that GnRH-II and its receptor do not stimulate gonadotropin secretion in vivo but instead elicit testicular steroidogenesis in an autocrine/paracrine manner. To elucidate the role of this novel ligand-receptor complex, our laboratory generated a transgenic swine line with ubiquitous knockdown (KD) of GnRHR-II. Testicular expression of GnRHR-II is reduced by 70% and males display primary hypogonadism; circulating concentrations of 10 gonadal steroids (progestogens, androgens, and estrogens) are ablated by 60 – 98% despite normal secretion of luteinizing hormone. These data suggest that GnRH-II and its receptor are critical modulators of steroidogenesis within porcine Leydig cells, yet the cellular and molecular mechanisms mediating this interaction remain undefined. Accordingly, the objective of this study was to analyze testicular transcriptomics of mature (> 300 d) GnRHR-II KD (n = 10) and littermate control (n = 7) boars via RNA sequencing. A gene or transcript was considered differentially expressed at FDR-adjusted P-value = 0.05. In total, 81,209 transcripts corresponding to 22,143 genes were identified within porcine testes. Of these, 74,496 were protein coding (39,158 known and 35,338 novel) while 6,713 were noncoding transcripts. Moreover, 1,843 novel noncoding (lncRNA) transcripts and 76 novel mRNA transcripts were identified. In total, there were 95 differentially expressed transcripts between GnRHR-II KD and littermate control boars—of which four were novel lncRNAs, 56 were novel mRNAs, and 35 were known transcripts. There were 24 differentially expressed genes (DEG)—six were novel while 18 had been previously annotated in the Sscrofa reference genome. Among them, 13 DEGs were up-regulated and 11 DEGs were down-regulated in GnRHR-II KD testes compared with control males. Up-regulated genes included those associated with mitochondrial function (LOC100524239) and enzymes in the ubiquitination pathway (USP42 and UBE2W). GnRHR-II was down-regulated in transgenic testes as well as as genes implicated in cancer (PUF60), cell adhesion (THBS1, CNTN1), and cellular growth and differentiation (EGR1, MSI2, FIBIN). Notably, genes that classically mediate steroidogenesis (e.g., StAR, CYP11A1) did not differ between genotypes. To conclude, this report elucidates the transcriptomics of swine testes revealing novel lncRNAs and mRNAs. Further, these data suggest that GnRHR-II KD does not impair gonadal steroidogenesis by merely down-regulating classic steroidogenic mediators. Instead, this study reveals novel candidate genes that may link GnRHR-II signaling with Leydig cell steroidogenesis. This report ultimately reveals the cellular and molecular consequences of GnRHR-II KD on porcine testis biology which could be harnessed to maximize boar fertility. Supported by USDA/NIFA AFRI-ELI predoctoral fellowship (2017-67011-26036; ATD) and AFRI (2017-67015-26508; BRW) funds. USDA is an equal opportunity provider and employer.